In the prior art, products for vehicles whose lighting function or indicating function is defined by standards, especially national standards, have already been proposed. Moreover, particularly in the automotive sector, the use of on-board computers has led to the introduction into vehicles of concepts derived from information technology. As a result, the product referred to as a headlamp or the product referred to as an indicating light has taken on a structure which has enabled it to be developed towards an on-board network architecture. Since then, the majority of vehicles have been fitted with a computer connected to various peripherals via an on-board network.
One example of an on-board network for vehicles is the CAN network. A network of this kind makes it possible, in particular, to reduce the number of conductors along which the signals and supply voltages pass, as regards the signals in particular by time multiplexing the information passing along the bus of the network.
Given the improvements to the lighting functions and indicating functions, the multiplication of different versions of the same vehicle, versions of the same light unit or versions of the same indicating light having different characteristics, new functions, each linked to lighting or indicating have already been proposed.
For example, the use of discharge lamps for lighting requires that the orientation of the light unit should be corrected in a dynamic manner in certain configurations so as to prevent drivers approaching the vehicle fitted with them from being dazzled by the lighting power of a light unit of this kind.
Use has therefore been made of the possibilities of extending the on-board network by adding one or more ancillary facility controllers, in this case, for example, to control one or more motors for correcting the attitude or orientation of the light unit relative to the chassis and/or to the road, each controlling electromechanical devices acting on the orientation of the light beam produced.
However, to connect each of these ancillary facility controllers to the electromechanical device associated with the light unit, it is necessary to use a harness for connecting the light unit to the network. As a result, the number of conductors in the vehicle increases with each function added to the light unit.
Since the lengths of these conductors can be significant, this results in an increase in the risk of electromagnetic interference, an increase in the risk associated with cutting wire harnesses for electrical connection when working on the vehicle, and a reduction in the reliability of operation, owing especially to cluttering of the engine compartment.
Moreover, for each additional function on a particular vehicle, it is necessary to calculate a new wire harness for electrical connection, and management of such a solution becomes prohibitive, especially with the multiplication of available options when purchasing a type of vehicle of the same make.
Furthermore, over and above questions of aesthetic appearance specific to each motor-vehicle manufacturer, the requirements of two motor-vehicle manufacturers can differ as regards the behaviour of the same lighting or indicating function, forcing the manufacturer of motor-vehicle components to develop a special type of light unit or light for each of them, increasing their design costs.
The invention provides a remedy to these disadvantages of the prior art. In the text which follows, it will be understood that the functions of lighting and indicating are similar as regards the problem posed and as regards the solution provided by the invention, unless otherwise stated.